Unreal Engine Issues
Unreal Engine Issues
Morph target is not applied on the first frame in Level Sequence
UE - Anim - Rigging - Dec 4, 2025When a skeletal mesh with morph targets spawns in the sequence, the morph is not reflected in the first frame. In the ProcessStage_SkinCache call of SkeletalMesh, MorphVertexBuffer->SectionIds is ...
Crash occurs loading a sublevel containing landscape with ray tracing enabled
UE - LD & Modeling - Terrain - Landscape - May 13, 2020In raytracing enabled, When loading a sublevel containing landscape with LoadStreamLevel function following error is shown. Assertion failed: Pair != nullptr [Link Removed] [Line: 584] Licensee re ...
GetStaticRayTracingGeometries doesn't check if mesh has ray tracing disabled
UE - Graphics Features - Ray Tracing - Nov 12, 2025An ensure is hit for static raytracing geometry because skeletal mesh assets that had ray tracing disabled were not handled in: FSkeletalMeshSceneProxy::GetStaticRayTracingGeometries The concurrent ...
Crash when a Deferred Decal (Translucent) base material has a Nanite Override (Masked Surface) Material and the mesh has Nanite + Ray Tracing enabled.
UE - Graphics Features - Ray Tracing - Aug 14, 2025A crash occurs when Nanite override material instance is used in a project with Ray tracing enabled where: 1 The Material assigned to the static mesh uses Deferred Decal / Translucent and the Nani ...
Point lights affect indirect lighting on RTGI much less than other types of lights
UE - Graphics Features - Lumen - Aug 4, 2020Only point lights affect indirect lighting on RTGI much less than other types of lights.[Link Removed] Indirect lighting of baked lightmaps look much stronger than RTGI.[Link Removed] Apparently, ...
Translucent materials in the PostMotionBlur pass can cause a flickering viewport artefact when using TAA
UE - Rendering - Graphics Features - Feb 5, 2025There appears to be a bug relating to rendering multiple windows that can trigger under unknown circumstances. It has been reported on rectangle lights in the forums and on PostMotionBlur materials ...
[CrashReport] UE4Editor_Engine!LoadSpecialMaterial() [unrealengine.cpp:1523]
UE - Graphics Features - Nov 10, 2017This is a longstanding crash that has occurred for more than 200 users since at least 4.13. Based on user descriptions this appears to permanently corrupt a project. User DescriptionsI just turned ...
Opcode shader compilation error when using a TextureSampleParameterCubeArray node with hardware ray tracing enabled
UE - Graphics Features - Ray Tracing - Mar 31, 2025Materials containing a cube array texture sampling node will not compile when hardware ray tracing is enabled. The shader compilation error indicates that an invalid op code was used: "Opcode Sample ...
Metahuman eyes black on close up with ray traced skylight.
UE - Graphics Features - Lumen - Jun 17, 2021[Substrate] Workaround for DXC problem with roll unlooping
UE - Graphics Features - Substrate - Apr 8, 2024We should get to the bottom of this workaround and revert it eventually. Reported here: [Link Removed] ...